Visual simulations in the two cerebral hemispheres: A bilingual perspective.

The ability of each hemisphere to construct visual simulations during first language (L1) and second language (L2) sentence reading was investigated. Late bilinguals read L1 and L2 sentences and decided after each sentence whether a pictured object was mentioned in the sentence. Target pictures were presented laterally in the left/right visual field (LVF/RVF) to the right/left hemisphere (RH/LH), respectively. 'Yes' responses were faster when the pictured object's shape matched, rather than mismatched, the sentence-implied shape, irrespective of the language involved. Critically, this visual shape effect was significant only under LVF/RH presentation, indicating that visual simulations are more likely to occur in the RH than in the LH. The fact that a similar experiment with central picture presentation has produced a significant shape effect only in the L1 (Norman & Peleg, 2022), suggests that under normal (central) reading conditions, the RH may be less involved in L2 than in L1 reading.

Lateralized reading in the healthy brain: A behavioral and computational study on the nature of the visual field effect.

Despite its widespread use to measure functional lateralization of language in healthy subjects, the neurocognitive bases of the visual field effect in lateralized reading are still debated. Crucially, the lack of knowledge on the nature of the visual field effect is accompanied by a lack of knowledge on the relative impact of psycholinguistic factors on its measurement, thus potentially casting doubts on its validity as a functional laterality measure. In this study, an eye-tracking-controlled tachistoscopic lateralized lexical decision task (Experiment 1) was administered to 60 right-handed and 60 left-handed volunteers and word length, orthographic neighborhood, word frequency, and imageability were manipulated. The magnitude of visual field effect was bigger in right-handed than in left-handed participants. Across the whole sample, a visual field-by-frequency interaction was observed, whereby a comparatively smaller effect of word frequency was detected in the left visual field/right hemisphere (LVF/RH) than in the right visual field/left hemisphere (RVF/LH). In a subsequent computational study (Experiment 2), efficient (LH) and inefficient (RH) activation of lexical orthographic nodes was modelled by means of the Naïve Discriminative Learning approach. Computational data simulated the effect of visual field and its interaction with frequency observed in the Experiment 1. Data suggest that the visual field effect can be biased by word frequency. Less distinctive connections between orthographic cues and lexical/semantic output units in the RH than in the LH can account for the emergence of the visual field effect and its interaction with word frequency.

Hemispheric Processing of Chinese Scientific Metaphors: Evidence via Hemifield Presentation.

The role of the two hemispheres in processing metaphoric language is controversial. In order to complement current debates, the current divided visual field (DVF) study introduced scientific metaphors as novel metaphors, presenting orientation mapping from the specific and familiar domains to the abstract and unfamiliar domains, to examine hemispheric asymmetry in metaphoric processing. Twenty-four Chinese native speakers from science disciplines took part in the experiment. The participants were presented with four types of Chinese word pairs: scientific metaphors, conventional metaphors, literal word pairs, and unrelated word pairs. The first word in each pair was presented centrally, and the second was presented to the left visual field (the Right Hemisphere) or the right visual field (the Left Hemisphere). Event-related potentials (ERPs) were recorded when participants read the target words and judged whether words in each pair were related. The data demonstrated that both hemispheres were involved at the initial stage of metaphor processing, but the right hemisphere took a more privileged role. The significant activation of the left hemisphere for scientific metaphoric processing supports the fine-coarse coding hypothesis. During right-visual-field presentation, the left hemisphere, responsible for the processing of closely related domains, has to integrate the loosely associated domains of scientific metaphor, which greatly increased cognitive taxes. Moreover, the data of late positive components (LPCs) revealed different hemispheric activation between scientific metaphors and conventional metaphors. Compared with literal pairs, conventional metaphors elicited significantly higher LPCs during right visual field presentation, while the scientific metaphor elicited significantly lower LPCs during left visual field presentation. These results suggest different processing mechanisms between novel metaphors and conventional metaphors and the special role of the right hemisphere in novel metaphoric processing at the later mapping stage.

Left Hemisphere Dominance for Negative Facial Expressions: The Influence of Task.

Major theories of hemisphere asymmetries in facial expression processing predict right hemisphere dominance for negative facial expressions of disgust, fear, and sadness, however, some studies observe left hemisphere dominance for one or more of these expressions. Research suggests that tasks requiring the identification of six basic emotional facial expressions (angry, disgusted, fearful, happy, sad, and surprised) are more likely to produce left hemisphere involvement than tasks that do not require expression identification. The present research investigated this possibility in two experiments that presented six basic emotional facial expressions to the right or left hemisphere using a divided-visual field paradigm. In Experiment 1, participants identified emotional expressions by pushing a key corresponding to one of six labels. In Experiment 2, participants detected emotional expressions by pushing a key corresponding to whether an expression was emotional or not. In line with predictions, fearful facial expressions exhibited a left hemisphere advantage during the identification task but not during the detection task. In contrast to predictions, sad expressions exhibited a left hemisphere advantage during both identification and detection tasks. In addition, happy facial expressions exhibited a left hemisphere advantage during the detection task but not during the identification task. Only angry facial expressions exhibited a right hemisphere advantage, and this was only observed when data from both experiments were combined. Together, results highlight the influence of task demands on hemisphere asymmetries in facial expression processing and suggest a greater role for the left hemisphere in negative expressions than predicted by previous theories.

Right visual field advantage for lexical decision dependent on stimulus size and visibility: Evidence for an early processing account of hemispheric asymmetry.

Previous research suggests that the right visual field advantage on the lexical decision task occurs independent of the visual quality of stimuli [Chiarello, C., Senehi, J., & Soulier, M. (1986). Viewing conditions and hemisphere asymmetry for the lexical decision. Neuropsychologia, 24(4), 521-529]. However, previous studies examining these effects have had methodological limitations that were addressed and controlled for in the present study. Participants performed a divided visual field, lexical decision task for words that varied in size (Experiment 1) and visibility (Experiment 2). Results showed a quality by visual field interaction effect. In both experiments, response times were faster for targets presented to the right visual field in the high quality (i.e., large font, high visibility) conditions; however, visual quality resulted in no differences for targets presented to the left visual field. Furthermore, this quality by visual field interaction effect was only observed when the target was a word. These results suggest that the left hemisphere advantage for lexical decision depends on the perceptual quality of targets, consistent with an early stage of processing account of hemispheric asymmetry during lexical decision. Findings are discussed within the context of word recognition and decision-based models.

Independent perceptual reversals for simultaneously presented ambiguous figures.

In two successive experiments using the divided visual field paradigm with vertical or horizontal division, two ambiguous figures, the Rubin's vase-face or the Necker cube, were projected to the right and left or to the upper and lower visual hemifields of 108 healthy volunteers. Stimulation time was 120 s. The main hypotheses were (a) that different percepts of the same ambiguous figure may be simultaneously experienced in the two hemifields and (b) that the type (vertical vs. horizontal) of visual field division influences the reversal frequency and the temporal interdependence of the percepts. Results from the first experiment showed that the temporal interdependence of reversals was very low for both ambiguous figures, suggesting that during part of the stimulation time the subjects could experience different percepts of the same figure (e.g. a vase in the right and face profiles in the left visual hemifields). The second experiment showed that this perceptual dissociation occurred on average during one third of the stimulation time. In both experiments the type of visual field division did not influence either frequency or temporal interdependence of the reversals. When one single ambiguous figure was presented in the centre of the screen, the number of reversals was approximately the sum of the reversals observed with two figures presented simultaneously each in one hemifield.

Lateralized embodiment of ambiguous human silhouettes: Data on sex differences.

Whereas the role of observers' sex has already been addressed in research on embodied cognition, so far it has been neglected as regards laterality effects in embodied cognition. Here, we report further analyses of the data used in our paper "Hemispheric asymmetries in the processing of body sides: A study with ambiguous human silhouettes" [1], where participants had to indicate the perceived orientation of silhouettes with ambiguous front/back orientation and handedness presented in the right and left hemifield. Specifically, the variables examined in the associated paper (the number of right- and left-sided silhouettes perceived as front- and back-facing in each hemifield; the number of silhouettes perceived as right- and left-handed in each hemifield) are analyzed by also factoring in participant's sex). Moreover, data are provided and analyses are performed both for the total sample of participants and for the sample of right-handed participants only. For further details, as well as for the interpretation and discussion of the data, the reader is referred to the main article [1] and its Supplementary Material.

Hemispheric asymmetry in holistic processing of words.

Holistic processing has been regarded as a hallmark of face perception, indicating the automatic and obligatory tendency of the visual system to process all face parts as a perceptual unit rather than in isolation. Studies involving lateralized stimulus presentation suggest that the right hemisphere dominates holistic face processing. Holistic processing can also be shown with other categories such as words and thus it is not specific to faces or face-like expertize. Here, we used divided visual field presentation to investigate the possibly different contributions of the two hemispheres for holistic word processing. Observers performed same/different judgment on the cued parts of two sequentially presented words in the complete composite paradigm. Our data indicate a right hemisphere specialization for holistic word processing. Thus, these markers of expert object recognition are domain general.

Emotion Words' Effect on Visual Awareness and Attention of Emotional Faces.

To explore whether the meaning of a word changes visual processing of emotional faces (i.e., visual awareness and visual attention), we performed two complementary studies. In Experiment 1, we presented participants with emotion and control words and then tracked their visual awareness for two competing emotional faces using a binocular rivalry paradigm. Participants experienced the emotional face congruent with the emotion word for longer than a word-incongruent emotional face, as would be expected if the word was biasing awareness toward the (unseen) face. In Experiment 2, we similarly presented participants with emotion and control words prior to presenting emotional faces using a divided visual field paradigm. Emotion words were congruent with either the emotional face in the right or left visual field. After the presentation of faces, participants saw a dot in either the left or right visual field. Participants were slower to identify the location of the dot when it appeared in the same visual field as the emotional face congruent with the emotion word. The effect was limited to the left hemisphere (RVF), as would be expected for linguistic integration of the word with the face. Since the task was not linguistic, but rather a simple dot-probe task, participants were slower in their responses under these conditions because they likely had to disengage from the additional linguistic processing caused by the word-face integration. These findings indicate that emotion words bias visual awareness for congruent emotional faces, as well as shift attention toward congruent emotional faces.

One is all you need: intrahemispheric processing benefits nonverbal visual recognition.

Several attempts have been made to understand when and how the two hemispheres of the brain work together to encode and retrieve information during memory tasks, but it remains unclear whether they are equally capable of encoding and retrieval, particularly when the stimuli do not evoke a leftward processing asymmetry. Using a divided visual field paradigm, we presented nonverbal visual stimuli to one visual field/hemisphere at encoding, and at retrieval presented the stimuli either to the same or opposite visual field/hemisphere. Recognition responses were faster and more accurate when the stimuli were initially presented at encoding and retrieval to the same hemisphere (Experiment 1), even when delay intervals between study and test were short (Experiment 2). Taken together, these findings suggest that recognition decisions for stimuli initially presented to a single hemisphere occur more quickly at shorter lags, perhaps due to a stronger memory representation in the original hemisphere of input compared to the indirectly activated hemisphere. Our results are significant because they demonstrate that each hemisphere of the brain can function to encode and retrieve memory representations equally well, as long as the stimuli contain no linguistic information.

Hemispheric processing in conventional metaphor comprehension: The role of general knowledge.

This study explored the relation between general knowledge and the hemispheric processing of metaphoric expressions in college age students. We hypothesized that prior knowledge influences how the hemispheres process metaphors in these individuals. In this study, 97 young (college-aged) adults completed a general knowledge and vocabulary test, and were then divided into high-knowledge/high-vocabulary and low-knowledge/low-vocabulary groups. Next, participants viewed word pairs consisting of conventional metaphors, novel metaphors, word pairs with a literal meaning, and unrelated word pairs. The first word in each pair was presented centrally, and the second was presented to the right visual field-left hemisphere (rvf-LH) or the left visual field-right hemisphere (lvf-RH), and participants indicated whether each pair was a meaningful expression. Accuracy results showed an interaction between general knowledge and visual-field hemisphere. Low-knowledge participants were more accurate for metaphors presented to the rvf-LH than the lvf-RH, whereas high-knowledge participants showed no accuracy differences between the hemispheres. We also found an interaction between vocabulary and visual field-hemisphere for conventional metaphors. Specifically, low-vocabulary participants showed a left-hemisphere accuracy advantage, but high-vocabulary participants showed similar accuracy patterns in both hemispheres. These results suggest that young adult readers who have more general knowledge process conventional metaphors similarly in both hemispheres, whereas young adult readers who have less general knowledge may rely more heavily on left-hemisphere processes during conventional metaphor comprehension.

Hemispheric asymmetry of liking for representational and abstract paintings.

Although the neural correlates of the appreciation of aesthetic qualities have been the target of much research in the past decade, few experiments have explored the hemispheric asymmetries in underlying processes. In this study, we used a divided visual field paradigm to test for hemispheric asymmetries in men and women's preference for abstract and representational artworks. Both male and female participants liked representational paintings more when presented in the right visual field, whereas preference for abstract paintings was unaffected by presentation hemifield. We hypothesize that this result reflects a facilitation of the sort of visual processes relevant to laypeople's liking for art-specifically, local processing of highly informative object features-when artworks are presented in the right visual field, given the left hemisphere's advantage in processing such features.

Lateralized Affective Word Priming and Gender Effect.

Affective priming research suggests that processing of affective words is a quick and short lived process. Using the divided visual field (DVF) paradigm, investigations of the lateralization of affective word processing have yielded inconsistent results. However, research on semantic processing of words generally suggests that the left hemisphere (LH) is the location where rapid processing occurs. We investigated the processing of affective (emotional) words using a combination of the DVF and affective priming paradigms, and four stimulus onset asynchronies (SOAs)-0, 150, 300, and 750 ms. The priming pattern yielded by males (n = 32) showed quick priming (at 0-ms SOA) of affective words in the LH; there was slower right hemisphere (RH) priming of affective words (at 750-ms SOA). In females (n = 28), both hemispheres were associated with quick priming of affective words (at 300-ms SOA in the LH and at 150-ms SOA in the RH). Results demonstrate the capability of both cerebral hemispheres in the processing of words with affective meaning, along with leading role of the left hemisphere in this process. This is similar to the results of semantic research that suggest access to word meanings occurs in both hemispheres, but different mechanisms might be involved. While the LH seems to prime affective words quickly regardless of gender, gender differences are likely in the RH in that affective word processing probably occurs slowly in males but rapidly in females. This gender difference may result from increased sensitivity to the emotional feature of affective words in females.

Hemispheric asymmetries in the processing of body sides: A study with ambiguous human silhouettes.

When required to indicate the perceived orientation of pictures of human silhouettes with ambiguous front/back orientation and handedness, both right- and left-handed participants perceive the figures more frequently as right-handed than as left-handed, which seems to indicate an attentional bias towards the right arm of human bodies. Given that past research exploiting the divided visual field paradigm indicated a processing advantage for contralateral body parts in both hemispheres, we tested whether human silhouettes with ambiguous handedness presented in the right visual field would be interpreted more frequently as right-handed compared with those presented in the left visual field. We confirmed the expected lateralised embodiment of ambiguous human bodies, in line with previous studies showing that right and left limbs are processed faster and/or more accurately when presented in the right and left hemifield, respectively.

Comprehension and Hemispheric Processing of Irony in Schizophrenia.

Studies focusing on the comprehension of figurative language among schizophrenia patients (SZ) reveal their difficulties comprehending such language and their tendency to interpret it literally. The present study investigated hemispheric processing and comprehension of irony in 16 SZ patients and 18 typically developing (TD) adults. Two experimental tasks were used: an online divided visual field experiment and an offline irony questionnaire. The results show an atypical reversal of hemispheric processing of irony in SZ patients as compared to TD adults. While the TD group demonstrated a right hemisphere advantage in processing irony, SZ patients demonstrated a left hemisphere advantage. Greater comprehension of irony was associated with decreased negative symptoms. In addition, under conditions that not involving a time restriction, the SZ patients' performance improved. Our findings reinforce those of previous studies suggesting that brain lateralization is atypical in SZ patients.

Hemispheric processing of predictive inferences: the influence of reading goals and textual constraint.

Recent findings suggest that textual constraint and reading goals influence inference generation. However, it is unclear how constraint and reading goals interact during predictive inference generation in the hemispheres. In the current divided visual field study, participants were given a study goal or not given a reading goal prior to reading text that was either strongly or weakly constrained toward a predictive inference. Participants then made lexical decisions to inference-related target words presented to either the left visual field-right hemisphere (LVF-RH) or the right visual field-left hemisphere (RVF-LH). When readers did not have a goal, strongly constrained inferences were processed similarly in the hemispheres, while a right hemisphere advantage was evident for weakly constrained inferences. However, when readers did have a goal, strongly and weakly constrained inferences were processed similarly in both hemispheres. Thus, goals of a reader seem to influence predictive inference generation in the hemispheres, particularly for weakly constrained text.

Hemispheric processing of predictive inferences during reading: The influence of negatively emotional valenced stimuli.

Although a left hemisphere advantage is usually evident during language processing, the right hemisphere is highly involved during the processing of weakly constrained inferences. However, currently little is known about how the emotional valence of environmental stimuli influences the hemispheric processing of these inferences. In the current study, participants read texts promoting either strongly or weakly constrained predictive inferences and performed a lexical decision task to inference-related targets presented to the left visual field-right hemisphere or the right visual field-left hemisphere. While reading these texts, participants either listened to dissonant music (i.e., the music condition) or did not listen to music (i.e., the no music condition). In the no music condition, the left hemisphere showed an advantage for strongly constrained inferences compared to weakly constrained inferences, whereas the right hemisphere showed high facilitation for both strongly and weakly constrained inferences. In the music condition, both hemispheres showed greater facilitation for strongly constrained inferences than for weakly constrained inferences. These results suggest that negatively valenced stimuli (such as dissonant music) selectively influences the right hemisphere's processing of weakly constrained inferences during reading.

Brain Activation Follows Adding-Type Integration Laws: Brain and Rating Responses in an Integration Task with pairs of Emotional Faces / La activación cerebral seguida a las leyes de integración tipo adición: Tasa de respuestas y actividad cerebral en una tarea de integración con pares de rostros emocionales

This study was designed to investigate the relation between rating responses and the patterns of cortical activation in an integration task using pairs of emotional faces. Participants judged on a graphic rating scale the overall affective intensity conveyed by two emotional faces, each presented to one of the two hemispheres via a Divided Visual Field technique (DVF). While they performed the task, EEG was recorded from 6 scalp locations. Three discrete emotions were considered (Joy, Fear, and Anger) and varied across three levels of expression intensity. Some face pairs portrayed the same emotion (same-emotion pairs), others two different emotions (distinct-emotions pairs). The patterns of integration of the two sources of information were examined both at the level of the ratings and of the brain response (event-related-α-desynchronization: ERD) recorded at each EEG lead. Adding-type rules were found for the ratings of both same-emotion and different-emotions pairs. Adding-type integration was also commonly found when α-ERD was taken as a response. Outcomes are discussed with a link to the lateralization of emotional processing and the relations between the observable R (e.g., ratings) and possible implementational aspects of the implicit r posited by Information Integration Theory (IIT).

El objetivo de este estudio fue investigar la relación entre la tasa de respuestas y los patrones de activación cortical en la integración de tareas usando los pares de expresiones faciales. Los participantes emitieron un juicio sobre una gráfica y la calificaron en una escala de intensidad afectiva que transmitía dos expresiones faciales, cada una se presentó a uno de los dos hemisferios usando la técnica de Divides Visual Field (DVF). Mientras ellos realizaban la tarea, fue grabada su respuesta en el EEG usando 6 electrodos. Tres emociones discretas fueron consideradas (Alegría, Miedo y Rabia) y estas variaron en tres niveles de intensidad de la expresión. Varios pares de caras contenían la misma emoción, otras dos mostraban emociones diferentes. Los patrones de integración de las dos fuentes de información fueron examinadas tanto con las escalas como con las respuestas cerebrales (ERD) grabadas en cada seguimiento del EEG. El patrón de la regla de la adición fue observado en las calificaciones de pares de emociones iguales y pares de emociones diferentes. La integración de tipo aditivo fue comúnmente observada cuando el α -ERD fue tomado como una respuesta. Los resultados fueron discutidos teniendo en cuenta la lateralización de los procesamientos emocionales y las relaciones entre la R observable y los posibles aspectos prácticos de r propuestos por la Teoría de Integración de la Información (IIT).

Upright or inverted, entire or exploded: right-hemispheric superiority in face recognition withstands multiple spatial manipulations.

Background. The ability to identify faces has been interpreted as a cerebral specialization based on the evolutionary importance of these social stimuli, and a number of studies have shown that this function is mainly lateralized in the right hemisphere. The aim of this study was to assess the right-hemispheric specialization in face recognition in unfamiliar circumstances. Methods. Using a divided visual field paradigm, we investigated hemispheric asymmetries in the matching of two subsequent faces, using two types of transformation hindering identity recognition, namely upside-down rotation and spatial "explosion" (female and male faces were fractured into parts so that their mutual spatial relations were left intact), as well as their combination. Results. We confirmed the right-hemispheric superiority in face processing. Moreover, we found a decrease of the identity recognition for more extreme "levels of explosion" and for faces presented upside-down (either as sample or target stimuli) than for faces presented upright, as well as an advantage in the matching of female compared to male faces. Discussion. We conclude that the right-hemispheric superiority for face processing is not an epiphenomenon of our expertise, because we are not often exposed to inverted and "exploded" faces, but rather a robust hemispheric lateralization. We speculate that these results could be attributable to the prevalence of right-handedness in humans and/or to early biases in social interactions.

The effects of intervention on the comprehension of irony and on hemispheric processing of irony in adults with ASD.

Individuals with autism spectrum disorders (ASD) experience difficulty in comprehending figurative language in general and irony in particular. The current study measured the effectiveness of a short-term intervention in enhancing the comprehension of irony. Twenty-nine adults with ASD and 22 typically developing (TD) adults participated in the study. Participants with ASD were randomly assigned to a study (intervention) or control (passive intervention) group. TD participants were also assigned to a passive intervention control group. The intervention improved comprehension of irony in the ASD group. Furthermore, responses to ironic and literal targets were similar within each hemisphere prior to the intervention within the ASD study group, but after the intervention responses lateralized to the right. Thus, following the intervention, participants with ASD demonstrated a pattern of hemispheric processing of ironic target words that resembled the pattern seen in the TD group prior to the intervention. Our findings suggest that an intervention that focuses on comprehension of irony improves performance of adults with ASD and affects the pattern of hemispheric processing of irony.